Structural steel derrick



Nov. 12, 1940. J. H. WILSON STRUCTURAL STEEL DERRICK Filed Feb. 19, 1938 2 Sheets-Sheet l Nov. 12, 1940. J. H. WILSON 2,221,067

STRUCTURAL STEEL DERRICK Filed Feb. 19, 1938 I '2 Sheets-Sheet 2 MW' l07an 71/125073 3% MM, *W

- bly. the purpose being to lower the cost of erection Pasta Nov. 12,1940

UNITED STATES PATENT OFFICE STRUCTURAL swam. naamcx John Hart Wilson, Wichita Falls, Tex. Application February 19, 1938, Serial No. 191,523

40mins (Cl. 189-16) The present invention relates to structuralsteel masts and to methods of and apparatus for fabricating and erecting such masts.

It has heretofore been generally the practice in the erection of structural steel masts of, various types, and particularly in the erection of masts of the type commonly designated oil field derricks, to transport the various structural mem-.

bers to the point at which the mast is to be erected and to there'assemble the members together,"piece by piece, the bottom members being first positioned and secured, and the upper members being successively added piece by piece until the mast or derrick has been completed.

Many of these derricks are of substantial height and there is a considerable element of danger to the'structural workers engaged in their erection. Likewise, by reasonof the fact that each structural worker must devote a large part of his effort to maintain his working position, when elevated a substantial distance above ground, his effectiveness in assembling the various individual struc-'- tural units inifinal position is decreased, the worker, in the average case, finding it necessary to use one hand in maintaining his position, leaving available one hand only to work with, thus increasing the cost and decreasing the speed of erection.

In accordance-with the present invention a structural steel derrick of novel construction is provided, together with a novel method of assemof such a structure, safeguard the structural workers engaged in such erection, and to greatly decrease the time necessarily expended inthe erection of a derrick of any given height and cross-sectional dimensions.

- The invention contemplates the assembling'together of the various structural units of which the derrick is composed at the point where the derrick is to be erected but, as distinguished from the prior methods of derrick erection above previously referred to, the derrick is built in two or more elongated sections which lie recumbent on the ground during fabrication and these sections are subsequently erected in a novel manner and rigidly secured together, theresulting derrick being even more rigid when finally completed than one of the same dimensions constructed in the manner heretofore employed. Also the derrick is so-put together that it may be readily disassembled when its usefulness at the spot of its erection is over. Substantial savings as well as increased safety are realized, therefore, both in the erection and in the dismantling of the derr ck.

As willlbe the novel derrick and method of erecting it may be modified invarious respects in the erection of apparent to one skilled in the art.

masts of different types intended for use for different specific purposes. That form of derrick which is illustrated in the accompanying drawings, therefore, is set forth by way of example only.

In the drawings:

Figure 1 is aside v ew showing in full lines the Figure 2 is a top plan view of the disassembledderrick and erecting means;

derrick sections just prior toerection and in Figure 3 is a section on line l-4 of Figure 1,

although on a larger scale;

Figure 4 is a side elevation of the upper portion of a raising or erecting mast, which comprises a portion of the erecting means for the main structure; l v

Figure 5 is a side elevation, upon a larger scale, of the upper end of-the completed derrick;

Figure 6 is a side elevation of a detail, showing the means for the attachment of the derrick sections; 3

Figure '7 is'a section on line 1-1 of Figure 1;

and a I Figure 8 is a section on line H of Figure 6.

The erected derrick shown in dotted linesin Figure 1 of'the drawings is of the type made use of in large numbers throughout the oil fields, and

commonly designated an oil field derrick. The

invention, however. may be employed in he erection of structural steelmasts of other types and designs and the details of construction of which 'vary materially from the details of the construction of the well-known oil field derrick, In every instance, however, the derrick will befa'bricated in sections,

secured to other similarly the sections being disposed horizontally and each comprising a longitudinally rigidshown) over the platform ing and casing pulling mechanism.

Two pairs of hinge elements are indicated at H, the axes of the hinge pins of each pair being in alignment and the axes of the two pairs being parallel. The truss members which together eventually comprise the -erected derrick are in-'- dicated at l2 and I3 respectively and it will be perceived that the adjacent ends of these truss members are connected to the hinges ll so that, when the truss members are moved from the positions in which they are shown in full lines in Figure 1 to the positions in which they are shown in dotted lines, they rock or swing about the parallel axes of the two setsof hinges.

The details of construction of the several truss members may be varied widely and it is only necessary that they shall be longitudinally rigid so as not to materially deflect while being swung upwardly into erect position about the hinges at their lower ends. Each truss is actually erected or constructed while horizontally disposed, the trusses being in alignment with each other. Assembling the various structural members in the fabrication of each truss may be most conveniently done inasmuch as much of the work involved in the bolting or otherwise fastening of the structural members together may be done by workers standing upon the ground. At the most short ladders are required and these are used only when the derrick is of such size that each individual truss component of the same has, when lying horizontally, course necessary, in constructing. longitudinally rigidtruss members, to provide each with both upper and lower longitudinal chords in order that the requisite stiffness may be obtained, as will be readily understood by those familiar with the construction of trusses. In general, however, the trusses may be constructed of any suitable elements and in any desired manner it being only essential to provide each with upper chords l2 and I3, each having an offset M, for purposes to be hereinafter described.

A raising mast or column is indicated-at l5, this mast being relatively small in cross-section as compared with the cross-section of the derrick, the lower end of this mast being suitably mounted upon the platform I intermediate the pairs of hinges I I. The raising mast is witha cross beam Hi to the outer ends of which are secured the downwardly and outwardly extending anchoring cables II, the lower ends of which are secured to anchoring devices l8 embedded in the ground so that the top of the raising mast I 5 is securely braced and maintained thereby in fixed position. Also mounted upon the raising mast, at the top .thereof, are pulleys or sheaves 20 and adjacent the bottom, pulleys or sheaves 2|. Elevating cables 22 extend from suitable winches or cable winding mechanisms (not ill, passing around antifriction rollers 23, thence around pulleys 2|, and upwardly through the raising mast to and over pulleys 20. These cables extend in opposite directions from pulleys 20, one extending downwardly to the derrick section l2 and the others extending downwardly to the derrick section IS, the lower ends of these cables being connected to a substantial height. It is of ropes may be clear, the chords 'choring cables I I.

provided at its top in which position the corresponding inner longitudinal chords of the two truss portions of the derrick are in contact. When so positioned, the derrick sections are detachably secured together and in Figures 5, 6 and 8 certain details of construction of thederrick, including the attachment means, are shown.

Thus the adjacent chords of the derrick sections, which are brought into contact when the I raising operation is completed, preferably comprise angle bars 2, the corresponding flanges of which are in contact and in'parallel relationship when the raising operation has been completed. Aligned cylindrical bores or apertures 26 are formed in the contacting angle sections and through each pair of aligned apertures a bolt 21 is projected, nuts being applied to tie the angle members together by means of the bolt. There may be as many of these securing bolts as is necessary to firmly and rigidly attach the derrick sections together into a single unitary structure. The securing devices may all be subsequently detached in the event that it is desired to disassemble the derrick and to lower its sections to the ground by reversingthe operation of erection.'

As it is necessary that the beam I6 secured to the top of the raising mast l5 shall have such length that. its. ends lie without the derrick when completely assembled, in order that the anchoring l2 and I3 of sections l2 and i3 are provided with the reentrant angles l4 orbfisets previously referred to, in order that these sections shall not strike the beam I6 when erected. In Figure 3 of the drawings the ends of beam I 6 are shown to protrude through the apertures in the derrick provided for the purpose, the ofisets I registeringtoprovide such apertures. After the derthe derrick rick has been erected in, the manner specified and the bolts 21 or other securing the raising cables are removed,

devices applied, likewise the an- The raising mast may then be taken down, section by section, or moved into one corner of the derrick, out of the way, but nevertheless in readiness to be repositioned when the derrick is to be dismantled.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In combination, a mast having its lower end detachably secured to the base centrally thereof, a horizontal beam mounted upon the upper end of said raising mast, supporting cables extending downwardly and outwardly from the outer ends of said beam to anchoring elements, whereby said raising mast is secured in position, means associated with the base for pivotally supporting the adjacent ends of horizontally disposed elongated trusses, and cables extending from the top of the raising mast to said trusses respectively whereby said trusses may be simultaneously rocked upwardly about said means, said trusses being longer than the rasing mast and having recesses to receive said beam when erected.

base, a vertical raising 2. A structural steel derrick comprising two identical elongated longitudinally rigid trusslike structures, each such structure having two longitudinal members adapted to be brought into engagement with the corresponding members of the other structure, and means for detachably securing said members together in pairs, the respective members of each said pair being formed with registering recesses.

3. A structural steel derrick mounted on a base and comprising upright and bracing members defining a vertically extending hollow structure having an opening extending transversely therethrough at a substantial distance from said base, said derrick being longitudinally separable into sections, a raising and lowering mast extending upward from said base and enclosed within said hollow structure, said mast having a horizontal beam at its upper end, the ends of said beam projecting outwardly through said opening, and supporting cables extending from the ends of said beam to anchoring elements.

4. The method of fabricating and erecting a structural steel derrick which comprises separately fabricating two rigid truss-like structures each to form one-half of the completed derrick, horizontally aligning said structures with adjacent ends' spaced apart, pivotally attaching such adjacent ends to fixed members, erecting a vertical raising mast intermediate said fixed members, said mast being of a height less than that of said derrick when erected and having a horizontal beam secured at the upper end thereof and extending at right angles to the center line of said structures, supporting said mast in position by cables extending from each end of said beam to anchoring points disposed laterally of said respective structures, simultaneously drawing said structures into vertical position by means of cables connecting each to the top of the raising mast, each said structure moving between said cables which extend to points disposed laterally of said respective structures, and securing said structures together in abutting relation, said structures being formed with mating recesses in their abutting portions to provide clearance for said beam, whereby said derrick when erected wholly encloses said mast and beam except the outer ends of the latter.

JOHN HART WILSON. 

